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UltravioletPhotography

Nikon Z6/Z7 as a UV/IR Conversion: the Bad News


Andrea B.

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The final test for me was exploring how the modified Z6 could handle close-up stacking using a powerful studio flash as the only light source.

 

I pressed some freshly sampled flowers of Gagea lutea (Yellow Star-of-Bethlehem) into use for this test, shot with the UV-Nikkor 105mm f/4 + PN-11 extension at 1:1.5 magnification, and selected the Broncolor 1600 Ws flash with uncoated Xenon tube as light source. The camera rig was bolted to a Stackshot controller.

 

I added a comparison done with the same lens and settings on my D3200 (internal Baader U). For the Z6, I used the UV-Nikkor with Baader U filter in front.

 

The stack comprised 23 frames shot at ISO 100 f/11. NEFs processed in latest incarnation of Photo Ninja (1.37a) and TIFs were stacked in Zerene Stacker.

 

Turned out that I had to add an extra EV of output to the Broncolor when doing the Z6 sequence. No problem as the flash ran on -4 EV setting already so plenty of available flash output if more was needed.

 

Flowers tend to move slightly, and the stack was too short to fully include the focus range necessary. I did not mind that too much as this was just a test.

 

First, the reference image with D3200.

 

T201904193764_D3200.jpg

 

Then, the same with Z6,

 

T20190419403_Z6.jpg

 

However, this is after the extra step of running the image through Topaz Denoise 6.01. The original had very obvious banding intact even after being massaged by Zerene Stacker. The 100% crop is shown below.

 

UV_banding_100ISO_Z6.jpg

 

I conclude that there is no way one can avoid the banding with this camera when it is run in low-ISO mode to get purportedly maximum image quality. Both camera did show the same UV-black basal patches with conical cells, though.

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I do have a Z6 that's full-spectrum converted (by Kolari Vision), but I have to admit I haven't had a chance to use it yet. (Waiting on a flash that's backordered, as well as a couple filters that are in the mail.) My applications are technical and indoors, so the banding isn't as likely to be an issue for me--the images don't need to be as aesthetic.

 

I wonder if the reason that different people are getting different results has anything to do with the firmware in the Z6--Nikon is currently at 1.01, and my camera came with 1.00--I just updated it. Perhaps Nikon made a few tweaks to the processing between sensor and .NEF file to reduce the incidence of banding. They've certainly been taking enough heat on the Internet for it.

 

Could you each possibly include the firmware revision when you post next?

 

Perhaps if the phase-detection AF is turned off, either through a menu selection (which I imagine Nikon would have to add-I didn't see on in the reference manual) or by choosing shooting conditions that cause the PDAF algorithm to switch over to contrast-detection, the banding would be different. Depends on how Nikon has coded the firmware; the bands would still be there since they come from the on-sensor PDAF pixels. If a different processing is applied for PDAF and CDAF focussing, then maybe the artifacts will be less intrusive for one or the other.

 

Regards,

dan kuespert

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I don't think changing the focus mode would affect the banding problem. This is due to the pixels them selves. I think Panasonic might be the best with out it all together. Second would be Canon, with every single pixel split, so no banding issue.

However, the Canon seems totally unusable for UV work, based on the Kolari teardown. I am still waiting for the Panasonic teardown, hoping it maybe ok. Having a Sigma L-mount camera option, next year really makes my consider that platform.

 

The reviews for the S1/S1r seem to be hitting the web now. In my opinion Panasonic has the best rear screen flip option. I love the simple tilt up and down of the Olympus Em1. I now hate the fully tilt out screen of the Olympus Em5 mk2 and E3. Being off axis is a real pain. These are basically fixed rear screens for me. But now I am ranting at what all reviews have as the only major negative.

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Apparently the modified Z6 does better when hooked up to a lens with IR filter. In this case the AFS 28-300mm f/3-5-5.6 Nikkor which I previously have used for IR work with excellent results. I tried it with B+w O-92 and O-93

 

These images were taken with the O-92 filter and f/11, 800 ISO, around 1/1000 sec. Hand-held camera.

 

T201904200432_AFS28-300_BWO-92_Z6.jpg

 

T201904200454_AFS28-300_BWO-92_Z6.jpg

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I don't think changing the focus mode would affect the banding problem. This is due to the pixels them selves. I think Panasonic might be the best with out it all together. Second would be Canon, with every single pixel split, so no banding issue.

...

 

No banding in Canon seems to be a myth, look at this comparison:

https://photographylife.com/the-reality-behind-nikon-z-banding-issues

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I tried it with B+w O-92 and O-93

These images were taken with the O-92 filter and f/11, 800 ISO, around 1/1000 sec. Hand-held camera.

 

At first I was confused by the O-92 and O-93 filter designations used.

They look like the Nikon naming style for orange filters, like the O-56.

 

May I offer a possible clarification?

I think you meant these filters:

(pasterd from the B+W handbook)

B+W Infrared Filter 092 (≈ 89 B ) [RG 695]

B+W Infrared Filter 093 (≈ 87 C ) [RG 830]

 

What post processing is done to reach these Aerochrome-like colours?

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Birna,

I think your making the correct decision here. However, I do wonder if this is a Z6 problem or a Lifepixel problem. Maybe you should message Dan Kuespert, since he got his Z6 from Kolari and see how it compares.

 

This is not really my topic of intense interest, but I have been mildly wondering all along, and just saying, just saying, I have been wondering if this might be some kind of LifePixel issue.

I have really liked LifePixel over the years, but I have had some issue in recent years, and so did Andy a while back, and I really have to wonder when things like that happen.

Frankly, I have had a camera that I have been wanting to convert for over a year, and I have hesitated about doing it, because of my past experience and such I have seen with Andy...

My feeling is that something may have changed there, hate to say, but I am just saying... Wondering? Just asking maybe more like?

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Andy Perrin
My issue with LifePixel was just that they should have tested infinity focus as a routine quality control measure. It would have caught their issue with using the wrong glass and saved them and me postage and time. By the way, Cadmium, I did email asking for a full refund as you suggested. They did not even bother to reply. I won’t be using them again.
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---

I think you meant these filters:

(pasterd from the B+W handbook)

B+W Infrared Filter 092 (≈ 89 B ) [RG 695]

B+W Infrared Filter 093 (≈ 87 C ) [RG 830]

 

What post processing is done to reach these Aerochrome-like colours?

 

You surmise correctly. For some reason, I tend to inset a '-' into the filter designation. Old habits die hard.

 

Colours? autolevels in PS, then a slight master hue shift.

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How long was Eve in Paradise? Shot IR with the 100mm f/1.6 Rodenstock today and lowered ISO to 200 as the lens lets a lot of light through ... B+W 093 filter (~Wratten 87C).

 

Heavy banding was immediately evident. Even stronger in presence for a follow-up shot at Low1 (~50ISO).

 

IR_banding_200ISO_ZUV0458_Rodenstock100mmf1,6_100pct_crop_Z6v1.jpg

 

My patience with this modification is now threadbare.

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The obvious question now is whether the issue is specific for a particular [defective?] camera unit, or the camera model as such.
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As my not modified Z6 showed the same banding in UV (FW 1.00), I assume it is a general issue.

 

If you zoom in on the banding on a pixel level, it is hardly seen, there are -kind of randomly- only some pixels a bit darker, and not all in the same line.

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And by the way: It seems the classic frequency analysis to get rid of the banding (DeNoise 6) is far superior compared to the artificial intelligence (DeNoise AI)
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And by the way: It seems the classic frequency analysis to get rid of the banding (DeNoise 6) is far superior compared to the artificial intelligence (DeNoise AI)

 

That saves us a few $$ ....

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At this time the real enigma to me is why my stock Z6 and Z7 cameras never have shown any indication of banding. They have been used all over the ISO range.
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Akira, the Panasonic is bigger and heavier. Not my ideal camera when arthritis strikes.

 

Indeed, S1/S1R are even slightly heavier than D850...

 

Hello, Akira !!!

 

Indeed, it has been awhile since we have talked. I hope all is well with you,

and that you still occasionally pursue a bit of IR or UV shooting. :)

 

I am indeed intrigued by this new S1/S1R line from Panasonic. I've always though my old (very) Panasonic G and my converted GH1 were so easy to learn and use. But I was always hoping for a better sensor. Will the S1 or S1R provide? It is looking good. And how nice it would be not to have PDAF banding. So we shall see, we shall see.

 

Andrea, unfortunately, I haven't shoot neither in UV or IR in recent years. But I've always been inspired by Birna and other folks' posts of the images of invisible lights. I have used Panasonic G1, GF5, GX8 and GH5, and, albeit some criticism, I like their contrast detect only AF method using the sensor with purely image taking pixels. The weight and the bulk are issues, though.

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That saves us a few $$ ....

 

If you owned a full version of Topaz Denoise, then you will get the new AI one for free. Topaz has been amazing at offering updates for free. I bought Denoise 4 and have, 5, 6 and now AI.

 

However, AI is really slow on my old computer. It takes 10 minutes to render if I move around. It also took about 10 hours to save a file, from .orf (Olympus input raw) to tiff. But this is an old computer. The AI can open raw and looks like version 1.02 doesn't have issues saving as DNG or Tiff. Going from jpg to jpg seems to take about 4 hours to save on my computer.

 

But for my computer version 6, I can actually use it in reasonable time (less than 10 minutes from edit to save) and it has Em1 and Df presents.

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My issue with LifePixel was just that they should have tested infinity focus as a routine quality control measure. It would have caught their issue with using the wrong glass and saved them and me postage and time. By the way, Cadmium, I did email asking for a full refund as you suggested. They did not even bother to reply. I won’t be using them again.

 

Thanks Andy. That is disconcerting. I have never used any other place, always felt fine about them, but here lately I am afraid to send them things. :-(

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Dabateman: However, I do wonder if this is a Z6 problem or a Lifepixel problem.

Cadmium: I have been wondering if this might be some kind of LifePixel issue.

 

In Post #1 I explained what causes the Z6 banding.* To review, that would be the Z6/Z7 software algorithm which attempts to correct for PDAF striping and produces in its place PDAF banding. In an unmodified Z6/Z7, the banding is not always obvious at higher ISOs. In a converted Z6/Z7 under a UV-pass filter, it seems that the inherent banding is exacerbated to the point of unusability no matter what ISO is used.

 

I don't understand how you can wonder whether conversion, per se, as performed by Life Pixel, Kolari Vision or MaxMax can cause a banding problem because conversion involves nothing more than removal of the internal UV/IR filter, removal of shaker or shaker glass (if any), addition of a clear glass filter and an adjustment to the sensor plane as needed for DSLR infinity focus. Conversion does not involve changes to boards or to software or firmware. So conversion cannot cause PDAF banding.

 

*to be clear - I provided the explanation of banding provided by Nikon, Jim Kasson, and other camera gear gurus. There are some references in Post #1.

 


 

The current failure by all three of Life Pixel, Kolari Vision and MaxMax: They are all three of them offering full spectrum conversions of an unsuitable camera, the Z6 (or Z7). Apparently none of the "big 3" converters ever test a particular full spectrum camera model under all three of UV, IR and Vis. Usually it is only IR that gets tested (it seems to me).

 

BETA TESTING BY THE CONSUMER IS A VERY BAD PRACTICE FOR ANY COMPANY TO FOLLOW. This really peeves me off. WHY is it always me or Birna who gets stuck "discovering" this stuff? The D700 IR-LED shutter monitor fog. The Coastal 60/4.0 hotspot. Etc. And now the incredible worsening of the Z6 PDAF banding problem under UV filters.

 

Oh well. Maybe we save a few readers of UVP from losing some money on bad gear? I hope so!

 

DO NOT CONVERT A Z6/Z7

 


 

Birna: At this time the real enigma to me is why my stock Z6 and Z7 cameras never have shown any indication of banding. They have been used all over the ISO range.

 

You apparently either (1) haven't been looking or (2) haven't been shooting in banding inducing conditions. The Z6/Z7 band is sporadic, almost rare, but you will eventually see it. Everybody else has. Just Google "Z6 banding" to get several pages worth of Z6 banding references across the web. (Ignore the refs about shutter banding.)

 

 

 

I also once discovered that a converted D200 could live through a dip into a duckweed covered frog pond. That was a nice discovery.

 

 

.

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Andy Perrin

The current failure by all three of Life Pixel, Kolari Vision and MaxMax: They are all three of them offering full spectrum conversions of an unsuitable camera, the Z6 (or Z7). Apparently none of the "big 3" converters ever test a particular full spectrum camera model under all three of UV, IR and Vis. Usually it is only IR that gets tested (it seems to me).

 

BETA TESTING BY THE CONSUMER IS A VERY BAD PRACTICE FOR ANY COMPANY TO FOLLOW. This really peeves me off. WHY is it always me or Birna who gets stuck "discovering" this stuff? The D700 IR-LED shutter monitor fog. The Coastal 60/4.0 hotspot. Etc. And now the incredible worsening of the Z6 PDAF banding problem under UV filters.

 

Indeed, and this is what annoyed me so much about my conversion: some very basic minimal testing would have caught the issue. They do NOT test these cameras thoroughly before sending them back.

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Dan: Perhaps if the phase-detection AF is turned off, either through a menu selection (which I imagine Nikon would have to add-I didn't see on in the reference manual) or by choosing shooting conditions that cause the PDAF algorithm to switch over to contrast-detection, the banding would be different. Depends on how Nikon has coded the firmware; the bands would still be there since they come from the on-sensor PDAF pixels. If a different processing is applied for PDAF and CDAF focussing, then maybe the artifacts will be less intrusive for one or the other.

 

The Z6 or Z7 can be forced into CDAF by setting the focus to "pinpoint". However, Jim Kasson (and others?) has seen the banding occur in CDAF also. Which is kind of weird given that the explanation for PDAF banding involves PDAF striping and that banding is not supposed to occur in CDAF.

 

And I'm not exactly sure what Z6/Z7 post-focus processing in the Z software or firmware is applied for the manual lenses we all use for reflected UV photography. Given that we are seeing massive Z6 banding with such stellar lenses as the UV-Nikkor or the CO 60, it must be the PDAF post-focus processing that is applied. Just guessing, though.

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Birna: How long was Eve in Paradise?

 

Eve was in Paradise for about 5 and a half minutes.

She had to leave to get her nails done so she could wow the snake.

 

 

.

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